A doctor may recommend genetic counseling or testing for any of the following reasons:
- A couple is planning to start a family and one of them or a close relative has an inherited illness. Some people are carriers of genetic illnesses, even though they don’t show, or manifest, the illness themselves. This happens because some genetic illnesses are recessive – meaning that they’re only expressed if a person inherits two of the problem gene, one from each parent. Someone who inherits one problem gene from one parent but a normal gene from the other parent won’t have symptoms of a recessive illness but will have a 50-50 chance of someday passing the problem gene on to their own children.
- An individual already has one child with a severe birth defect. Not all children who have birth defects have genetic problems. Sometimes, birth defects are caused by exposure to a toxin (poison), infection, or physical trauma before birth. Even if a child does have a genetic problem, there’s always a chance that it wasn’t inherited and that it happened because of some spontaneous error in the child’s cells, not the parents’ cells.
- A woman has had two or more miscarriages. Severe chromosome problems in the fetus can sometimes lead to a spontaneous miscarriage. Several miscarriages may point to a genetic problem.
- A woman has delivered a stillborn child with physical signs of a genetic illness. Many serious genetic illnesses cause specific physical abnormalities that give an affected child a very distinctive appearance.
- A woman is pregnant and over age 34. Chances of having a child with a chromosomal problem (such as trisomy) increase dramatically when a pregnant woman is older.
- A child has medical problems that might be genetic. When a child has medical problems involving more than one body system, genetic testing may be recommended to identify the cause and make a diagnosis.
- A child has medical problems that are recognized as a specific genetic syndrome. Genetic testing is performed to confirm the diagnosis. In some cases, it also may aid in identifying the specific type or severity of a genetic illness, which can help identify the most appropriate treatment.